{"_meta":{"attribution":"Data aggregated by pdata.world (https://pdata.world) from 8 prediction-market venues; CC BY 4.0; source data © each venue.","canonical_url":"https://pdata.world/events/polymarket/1199455","as_of":"2026-10-19T14:55:06.403828Z","docs":"https://api.pdata.world/docs","cite_as":"According to pdata.world (tracking Polymarket): \"S&P 500 (SPX) Opens Up or Down on October 19?\" — 100% as of 2026-10-19 UTC. https://pdata.world/events/polymarket/1199455","source_url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-19-2026"},"source":"polymarket","id":"1199455","ticker":"spx-opens-up-or-down-on-october-19-2026","slug":"spx-opens-up-or-down-on-october-19-2026","title":"S&P 500 (SPX) Opens Up or Down on October 19?","description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on October 19 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nThis market will resolve to \"Down\" if the official S&P 500 Index open price for S&P 500 (SPX) on October 19 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nE.g., ordinarily, a market on Monday would refer to the previous Friday for its most recent closing price, unless that Friday were a market holiday, in which case it would refer to Thursday, or the next most recent trading day.\n\nIf the two prices are exactly equal, this market will resolve 50-50. Note that all figures will be rounded to the nearest cent using standard rounding.\n\nIf SPX does not trade at all during the regular session, the market will resolve 50-50.\n\nIf either of the relevant days are shortened (for example, due to a market holiday schedule), the official open/close price published by S&P 500 Index for that shortened session will still be used for resolution.\n\nIf the previous trading day has no official closing price (for example, due to a trading halt into the market close, system issue, delisting, or other disruption), the market will use the last valid on-exchange trade price of the regular session as the effective closing price.\n\nThe resolution source for this market is the Wall Street Journal, specifically the Open/Close values published by the WSJ under \"Historical Prices\".\n\nUS: https://www.wsj.com/market-data/stocks\nEMEA: https://www.wsj.com/market-data/stocks/emea\nASIA: https://www.wsj.com/market-data/stocks/asia","image":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","icon":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","active":true,"closed":false,"start_date":"2026-10-16T12:00:58Z","end_date":"2026-10-19T20:00:00Z","closed_time":null,"volume":5882.908746000001,"volume_24hr":5872.908746,"volume_24h_change":null,"normalized_vol_24hr":28.523418426513672,"normalized_volume":17.113889694213867,"liquidity":22107.41769,"open_interest":3242.174288,"categories":["Finance"],"tags":[{"id":"102683","slug":"spx","label":"SPX"},{"id":"102127","slug":"up-or-down","label":"Up or Down"},{"id":"102281","slug":"daily","label":"Daily"},{"id":"102682","slug":"indicies","label":"Indicies"},{"id":"120","slug":"finance","label":"Finance"},{"id":"102169","slug":"hide-from-new","label":"Hide From New"}],"synthetic":false,"is_group":false,"group_key":null,"parent_event_id":null,"probability":null,"spread":null,"top_outcome":"","top_outcome_probability":0.9995,"top_outcome_prob_24h_change":0.6945000000000001,"top_outcome_volume_24h_change":5842.908746,"updated_at":"2026-10-19T14:05:34.167867Z","fetched_at":"2026-10-19T14:05:34.167867Z","added_at":"2026-10-16T12:25:49.965095Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-19-2026","chart_24h":[10.0,10.0,10.0,10.0,10.0,10.0,30.0,90.0,266.25,266.25,412.5,412.5,412.5,422.5,537.5,758.306248,758.3062480000001,1121.028468,1218.594341,1253.594341,1253.594341,1253.594341,1319.643626,1366.233626,1486.233626,1701.233626,1754.19296,1754.19296,1764.376237,2314.487294,4250.811479,4453.712079,5872.908746],"kind":"live","mutually_exclusive":false,"markets_total":1,"markets":[{"source":"polymarket","id":"5773011","event_id":"1199455","slug":"spx-opens-up-or-down-on-october-19-2026","question":"S&P 500 (SPX) Opens Up or Down on October 19?","group_item_title":null,"description":"This market will resolve to \"Up\" if the official S&P 500 Index open price for S&P 500 (SPX) on October 19 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nThis market will resolve to \"Down\" if the official S&P 500 Index open price for S&P 500 (SPX) on October 19 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day.\n\nE.g., ordinarily, a market on Monday would refer to the previous Friday for its most recent closing price, unless that Friday were a market holiday, in which case it would refer to Thursday, or the next most recent trading day.\n\nIf the two prices are exactly equal, this market will resolve 50-50. Note that all figures will be rounded to the nearest cent using standard rounding.\n\nIf SPX does not trade at all during the regular session, the market will resolve 50-50.\n\nIf either of the relevant days are shortened (for example, due to a market holiday schedule), the official open/close price published by S&P 500 Index for that shortened session will still be used for resolution.\n\nIf the previous trading day has no official closing price (for example, due to a trading halt into the market close, system issue, delisting, or other disruption), the market will use the last valid on-exchange trade price of the regular session as the effective closing price.\n\nThe resolution source for this market is the Wall Street Journal, specifically the Open/Close values published by the WSJ under \"Historical Prices\".\n\nUS: https://www.wsj.com/market-data/stocks\nEMEA: https://www.wsj.com/market-data/stocks/emea\nASIA: https://www.wsj.com/market-data/stocks/asia","image":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","icon":"https://polymarket-upload.s3.us-east-2.amazonaws.com/s-and-p-500-1e40af6979.png","outcomes":["Up","Down"],"outcome_prices":[0.9995,0.0005],"probability":0.9995,"spread":0.001,"active":true,"closed":false,"start_date":"2026-10-16T12:00:58Z","end_date":"2026-10-19T20:00:00Z","closed_time":null,"result":null,"volume":5882.908746000001,"volume_24hr":5872.908746,"prob_24h_change":0.6945000000000001,"volume_24h_change":5842.908746,"normalized_vol_24hr":28.220762252807617,"normalized_volume":22.104734420776367,"liquidity":22107.41769,"categories":["Finance"],"countries":[],"updated_at":"2026-10-19T14:05:34.423806Z","fetched_at":"2026-10-19T14:05:34.423806Z","added_at":"2026-10-16T12:25:50.095954Z","url":"https://polymarket.com/event/spx-opens-up-or-down-on-october-19-2026/spx-opens-up-or-down-on-october-19-2026","event_title":"S&P 500 (SPX) Opens Up or Down on October 19?","chart_24h":[0.305,0.4,0.38,0.5,0.77,0.85,0.94,0.845,0.945,0.9645,0.9495,0.95,0.9145,0.904,0.917,0.9745,0.9715,0.9515,0.974,0.9815,0.97,0.987,0.9935,0.9995]}]}